Travel control apparatuses for automatically performing lane change of a vehicle have been conventionally known. Such a travel control apparatus may use a known technique of determining whether or not a space for lane change exists in an adjacent lane to the lane in which the vehicle travels and executing the lane change when the space for lane change exists in the adjacent lane (see WO2010/082353).
In the above conventional technique, even when another vehicle travels in an adjacent lane to the lane in which the subject vehicle travels and the other vehicle is highly likely to change lanes to the next lane adjacent to the adjacent lane (next adjacent lane), the subject vehicle is not permitted to change lanes until the other vehicle actually changes lanes to the next adjacent lane and a space for lane change is detected in the adjacent lane. As a consequence, the subject vehicle may not be able to smoothly change lanes.